1. Field of the Invention
The present invention relates generally to the field of information storage devices, and more particularly to head stack assemblies used in such devices.
2. Background of the Art
Information storage devices are used to retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive is an example of an information storage device that includes one or more heads that can both read and write, but other information storage devices also include heads—sometimes including heads that cannot write.
In a modern magnetic hard disk drive device, each head is a sub-component of a head-gimbal assembly (HGA) that typically includes a laminated flexure to carry the electrical signals to and from the head. The HGA, in turn, is a sub-component of a head-stack assembly (HSA) that typically includes a plurality of HGAs, an actuator, and a flex cable. The plurality of HGAs is attached to various arms of the actuator, and each of the laminated flexures of the HGAs has a flexure tail that is electrically connected to the HSA's flex cable.
Modern laminated flexures typically include conductive copper traces that are isolated from a stainless steel structural layer by a polyimide dielectric layer. So that the signals from/to the head can reach the flex cable on the actuator body, each HGA flexure includes a flexure tail that extends away from the head along the actuator arm and ultimately attaches to the flex cable adjacent the actuator body. That is, the flexure includes traces that extend from adjacent the head and terminate at electrical connection points at the flexure tail. The flex cable includes electrical conduits that correspond to the electrical connection points of the flexure tail.
Each flexure tail is physically held adjacent a supporting actuator arm, typically by adhesive tacking. If the flexure tail is not adequately secured to the actuator arm, air induced by disk rotation can cause the flexure tail to excessively flutter. Excessive flutter is undesirable because it can lead to excessive vibration of adjacent components, causing dynamic disturbances that can induce read/write errors. Excessive flutter may also cause contact locations between the flexure tail and actuator arm to wear, thereby generating debris particles that can undesirably contaminate the head/disk interface. On the other hand, adhesive tacking is undesirable because it is both a risky and cumbersome manufacturing process in a high-volume manufacturing environment. Disk drive components are typically assembled in clean rooms because small amounts of contamination can result in manufacturing yield loss due to interference with the operation of sensitive and high-precision components such as magnetic recording heads. Control of the spread of adhesive and its constitutive chemicals represents a formidable challenge in high volume disk drive manufacture, and therefore processes that require adhesive are not favored.
Accordingly, there is a need in the art for improved flexure tail and actuator arm configurations to facilitate securing the flexure tail(s) to corresponding actuator arms with reduced need for adhesive tacking.